June 24, 2008

Interpreting a 1H-1H COSY spectrum … Part 3

A 1H-1H COSY dataset of an unknown structure with protons offers many combinations of atom connectivity. The goal for the elucidator is to assess the correlations and narrow down a set of fragments that support the data.

Below is a structural list for 1H to C to 1H connectivities. Absent from the list, heteroatoms such as O, N and S should also be considered. The 2J coupling, the 3J coupling, outlined with a blue box, the 4J coupling, outlined in a green box, and the 5J coupling, outlined with a purple box, offers 1, 3, 6 and 14 possible combinations, respectively.